关键词: 交通状态, 区际联系, 通达性, 城市道路网, 南昌市

Abstract:

：Traffic is a prerequisite for the development of a city. Nowadays, the construction of highways, national roads and other high-grade roads has strengthened the connectivity between cities. Nevertheless, due to the increasing demands for traffic inside the city, the heavy traffic of inner city has weakened the connectivity greatly. Therefore, the traffic conditions inside the city have become one of the most important restraining factors of the interregional connection. The accessibility is an effective indicator which measures the convenient degree of the road networks. This paper aims to comprehensively analyze the three factors influencing accessibility, which are the diurnal variation of traffic state, the grade of interregional entrances in Nanchang, and some special routes such as highways, bridges and tunnels. Then it studies the spatial distribution of interregional contact accessibility of the urban area, based on the road saturation and the minimum time distance models. Based on the result of the interregional contact accessibility in Nanchang, this paper gives an in-depth analysis of the accessibility to different grades of interregional entrances in the core area of Nanchang city. In order to promote the interregional accessibility of the city, this paper also provides references for traffic organization optimization. The results show that the spatial pattern of interregional contact accessibility in Nanchang is following with the extension of the main road, but this kind of extension would fade in the rush hour. Interregional contact accessibility of the core area in Nanchang is the highest, and gradually decreasing from the center area to the surroundings. However, the value of accessibility in the whole area is affected by the traffic state of the 51 main roads in old Nanchang region, and the spatial structure of the accessibility varies with hours, especially in core area of Nanchang. Meanwhile, the state of bridges and tunnels also affect the accessibility greatly. The crowding of bridges and tunnels shows the block caused by the river and the railway line, because of the distinct difference of the accessibility between both sides of the river and the railway line in the rush hour. Generally speaking, the accessibility in the core area of Nanchang is well, and the accessibility of Honggutan District is much better than that of the old Nanchang region especially in the rush hour because of the higher road grade and the lighter traffic.

Key words: traffic state, interregional contact, accessibility, urban road network, Nanchang